System Analysis Knowledge Bytes: NEW COURSE - PDN and Voltage Ripple Analysis

The System Analysis Knowledge Bytes blog series explores the capabilities and potential of the System Analysis tools offered by Cadence. In addition to providing insight into the useful features and enhancements in this area, this series aims to broadcast the views of different bloggers and experts, who share their knowledge and experience on all things related to System Analysis.

Apples to apples. This was the theme of a webinar that I hosted last year for voltage ripple analysis with Sigrity X SystemPI. Signal and power integrity engineers historically utilized power delivery network (PDN) plots to validate a system's voltage ripple performance. It was assumed that if a system's frequency response was held below a certain threshold impedance, then the voltage ripples of the system would be within reasonable margins. This would be confirmed as lab voltage ripple measurements. However, this comparison is between the frequency domain and the time domain, like comparing apples to oranges. The new course, PDN and Voltage Ripple Analysis with Sigrity X OptimizePI and SystemPI, aims to teach you how to utilize OptimizePI and SystemPI to generate both PDN profiles in the frequency domain and voltage ripples in the time domain, allowing you to compare simulated voltage ripples to lab voltage measurements. Apples to apples.

What's in the New Course?

This course is the second part of a renewed series on power integrity and focuses on its AC realm. You will first address the frequency domain by developing PDNs, adding additional frequency-dependent components that alter the PDN, and by optimizing the decoupling schemes of a design by utilizing OptimizePI. You will then use SystemPI to learn the tool's uses in both the frequency and time domains. You will create and modify a PDN and generate a threshold or target impedance for your design. You will then simulate the design's voltage ripple and see how the voltage ripples change as the PDN is modified throughout the course.

Why Two Different Tools?

The major differences between the OptimizePI and SystemPI tools are in their capabilities and how they model your design. OptimizePI is renowned for its ability in optimizing your decoupling design to meet user-defined criteria, such as cost or total number of components. This tool relies on a board layout file as well as capacitor models to maximize its potential.

SystemPI can be viewed as an extension of OptimizePI, specializing in simplifying complex multi-layout, multi-die designs and the ability to simulate voltage ripples. SystemPI is a block-based modeling tool, which allows for quick modeling and simulations because all of the building blocks of the design are captured as abstracted blocks; your layout file can be an S-parameter, your package can be a SPICE file, and your VRM can be an ideal voltage source, all of which can be connected simply with lines between their appropriate ports and terminal nodes.

Who Should Take the Course?

This course replaces a portion of the popular Sigrity PowerDC and OptimizePI course. As such, this course is designed for anyone that's interested in power integrity, and will particularly help signal and power integrity engineers that want to grow deeper in their power integrity analysis skills in the AC realm. This course also introduces SystemPI, which has the capability to simulate voltage ripples so this course provides benefit for anyone curious about the time domain simulations of a power delivery system.

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